I can take my Garmin out the car and walk around with it but it's not as convenient as the PSP that I'm going to take around while listening to music, playing games, watching movies and whatever else.

It is just another element to add to the PS3 and like EZ said, most cell phones have it all ready but it's cool to have a device that has it all instead of carrying 5 devices. You can have your PSP and your cell and you pretty much have everything that a gadget whore could ever need.